Patent GB-1064280-A (GB)
Title: Improved control system
IPC: G11B27/029
Filed: 1964-10-14
Abstract: 1,064,280. Recording and editing animated video signals; electronic counters. AMPEX CORPORATION. Oct. 14, 1964 [Dec. 9, 1963], No. 41909/64. Headings G4A and G5R. A system of recording and editing animated video signals on a tape is controlled by programme and editor units 32 and 34, Fig. 1, which count the cue pulses recorded with each frame so that the various record and playback heads may be energized at appropriate times as determined by their physical displacement along the length of the tape. When it is desired to record a further X frames on a tape, the tape is started and cue pulses from previously recorded frames are detected by head 30 and pass to the programme unit 32. When cue pulses cease to arrive, thereby indicating the end of the previously recorded sequence, edit pulses at one frame intervals initiated by a synchronizer 35 are counted in unit 32. After a count of 23, which corresponds to the sum of the distances between the cue record head 16 and video head 20 (18 frames) and between the cue playback head 30 the video erase head 26 (5 frames), an editor start pulse is produced which resets the counter, energizes the video erase head, and starts a counter in the editor unit which turns on the recording switch 24 and the cue record head 16 after a further 18 frames. When the counter in unit 32 reaches the preset value of X, an editor stop pulse is produced which restarts the counter in the editor unit which after 18 frames opens switch 24, de-energizes the cue record head 16 and video erase head 26, and may stop the tape drive. A mode selector 29 allows the control system to be switched into a condition where it deletes the last X frames of a previously recorded sequence. The counter in unit 32 is then set to the value X, and in response to the first missing cue signal counts from X up to 37, there being 37 frames between the cue playback head 30 and the cue erase head 28. When the counter reaches 37 an output pulse energizes the cue erase head and the video erase head. Electronic counter.-A binary counter 61, Fig. 4, is coupled through a diode matrix 62 to a two-pole multi-position switch arrangement 103A and 103B, the connections being such that in one mode of operation an output is provided on line 65 when the counter 61 reaches a number set on the switch arrangement, and that in another mode of operation an input pulse on line 65 sets the counter from zero to the number set on the switch arrangement. Each stage of the counter comprises a pair of intercoupled transistors the state of which can be inverted by a signal applied to both bases. A reset signal may be applied to one collector, and the other collector provides an output through an equalising resistor 101 to the diode matrix. The output of the first stage is connected to all the odd-numbered positions of switch 103A, the armature 108 of which is connected to junction number 1. The odd-numbered positions of switch 103B are connected to the corresponding numbered junctions of the matrix, the even-numbered positions are connected to the next higher odd numbered positions, and the armature 109 is connected to an output/input line 65. The diode matrix is so arranged that a particular numbered junction is earthed only when the counter 61 records the corresponding number; in all other states of the counter a conduction path exists between the junction and a negative output of the counter. Consequently, line 65 is earthed only when the counter reaches the number set on the switches 103A and 103B. In the other mode of operation, the counter is set to zero by a reset pulse and a positive pulse (i.e. rising from negative to earth or slightly positive) on line 65 sets the counter to the number set on the switches.